Topics

General Knowledge
General Science
General English
Aptitude
General Computer Science
General Intellingence and Reasoning
Current Affairs
Exams
Elementary Mathematics
English Literature

Two inlet pipes fill a cistern in 10 minutes and 15 minutes respectively. An outlet pipe empties the cistern in 5 minutes. All three pipes are opened together when the cistern is full. In how many minutes will the cistern be emptied?

A) 30 minutes
B) 25 minutes
C) 27 minutes
D) 18 minutes

Correct Answer:

A) 30 minutes

Description for Correct answer:
The two inlet pipes can fill the cistern in 10 min and 15 min respectively and the outlet pipe can empty at the rate of 5 min.

When all 3 pipes are kept open simultaneously, the quantum of water filled in 1 minute = \( \Large \frac{1}{10}+\frac{1}{15}-\frac{1}{5}=\frac{-1}{30}\ or\ \frac{1}{30} \)th of the tank gets emptied in a minute.

Therefore, the cistern will empty in 30 minutes.

Part of solved Pipes and Cisterns questions and answers : >> Aptitude >> Pipes and Cisterns

Comments

Similar Questions

1). A crack at the bottom of a cistern can empty it in 3 hours. A fill tap that fills water at the rate of 10 litres/min is turned on when the cistern is full and now it takes 6 hours for the tank to empty. What is the capacity of the tank?

A). 2400 Ltrs.

B). 3600 Ltrs.

C). 1200 Ltrs.

D). 2000 Ltrs.

2). A pipe normally takes B hours to fill a tank. However, due to a crack at the bottom it takes 2 more hours. How long will the crack at the bottom of the tank take to empty a full tank when the fill pipe is kept shut?

A). 20 Hrs.

B). 36 Hrs.

C). 40 Hrs.

D). 48 Hrs.

3). Pipe A can fill a tank in 20 minutes and pipe B can fill the same tank in 30 minutes. If pipe A is opened and 8 minutes later pipe B is also opened, then in how many minutes will the tank be full?

A). 13.4 minutes

B). 16.8 minutes

C). 12.9 minutes

D). 15.2 minutes

4). Three fill pipes A, B and C fill a tank in 4, 6 and 8 minutes respectively. Pipe A is opened and after a minute, Pipe B is also opened. Another minute later, Pipe C is also opened. When will the tank be full?

A). \( \Large 2\frac{8}{13} \)

B). \( \Large 1\frac{11}{13} \)

C). \( \Large 3\frac{2}{13} \)

D). \( \Large 1\frac{8}{13} \)

5). Two fill pipes A and B can fill a tank in 12 minutes and 15 minutes respectively. A drain pipe at the bottom when opened in tandem with the two fill pipes will result in the tank getting filled in 12 minutes. How long will the drain pipe take to empty the tank?

A). 12 minutes

B). 15 minutes

C). 18 minutes

D). 20 minutes

6). Pipe A and Pipe B fill a tank in 16 and 24 minutes respectively. Another pipe at the bottom, Pipe C drain the tank at the rate of 25 liters per minute. If all three of them are opened simultaneously. then the tank will be full 12 minutes. What is the capacity of the tank?

A). 1000 Ltrs.

B). 2000 Ltrs.

C). 1200 Ltrs.

D). 1600 Ltrs.

7). Pipe A will fill a tank in 24 minutes and Pipe B will fill the same tank in 36 minutes. There is a drain pipe at the bottom which will empty the tank in 30 minutes. lf the drain pipe is opened 8 minutes after pipe A and pipe B are opened, when will the tank be full?

A). 18.6 minutes

B). 15.9 minutes

C). 17.5 minutes

D). 20.3 minutes

8). Two pipes A and B fill a tank. Pipe A fills the tank thrice as fast as Pipe B. lf both pipes are kept open together when the tank is empty, the tank will be full in 18 minutes. How long will pipe B alone take to fill the tank?

A). 72 minutes

B). 64 minutes

C). 58 minutes

D). 50 minutes

9). A pump can be used either to fill or to empty a tank. The capacity of the tank is 3600 \( \Large m^{2} \). The emptying capacity of the pump is 10 \( \Large \frac{m^{2}}{min} \) higher than its filling capacity. What is the emptying capacity of the pump if the pump needs 12 more minutes to fill the tank than it takes to empty the tank?

A). \( \Large 40 m^{3}/min \)

B). \( \Large 60 m^{3}/min \)

C). \( \Large 80 m^{3}/min \)

D). \( \Large 100 m^{3}/min \)

10). Pipe A can fill the tank in 30 minutes and pipe B can fill the same tank in 20 minutes. Both the pipes are kept open simultaneously. When should pipe B be switched off, so that the tank may fill in exactly 24 minutes?

A). 5 minutes

B). 7 minutes

C). 4 minutes

D). 3 minutes